System for transmitting tire condition variables
The present invention relates to a system for transmitting tire condition variables from a transmission device mounted on a motor vehicle to an electronic evaluating or control unit arranged in the area of the vehicle body, which is detachably fastened to a motor vehicle wheel described hereinbelow for providing an electromechanical compound arrangement. Further, a transmission device is disclosed wherein tire condition variables can be detected, and wherein a coupling device is integrated into the wheel hub (3) and composed of a rotor and a non-rotating stator for producing a field coupling, and its one or more field coupling elements are arranged opposite one another, separated by a narrow air slot (24), and energy and/or signals are coupled by means of electric fields and/or magnetic fields and/or electromagnetic fields. Still further, the system contains a vehicle wheel equipped with sensors, consisting of wheel rim (1), pneumatic tire (2), and a sensor subassembly (13, 13′, 14, 15, 44) which rotates with the wheel. The wheel has a signal connection that can be connected to the transmission device.
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The present invention relates to a transmission device, a vehicle wheel equipped with sensors, and a system for transmitting tire condition variables.
It is known, among others, from EP-A-0 806 307 to transmit tire condition variables such as pressure or temperature into the interior of a motor vehicle, for example, to an electronic evaluating or control unit. The arrangement described in EP-A-1 227 944 can also measure driving-dynamics tire quantities or wheel condition quantities such as lateral tire force, longitudinal force (wheel torque) or forces that act in a radial direction on the tire (wheel contact force). In both cases, the data to be transmitted is primarily meant for the automated increase of vehicle safety by electronically controlled brake reactions. In addition, there is the possibility of indicating to the driver any information that is interesting to the driver such as about the measured tire pressure, by way of separate display units. Among others, physical conditions such as inside air pressure, air temperature, temperature of the tire rubber, rubber deformations, noise spectra are considered herein as tire condition variables just as well as characteristics or markings such as tire characteristics, from which age, structural shape, type (summer/winter tire) can be taken.
In a tire pressure control system (TPMS) according to EP-A-0 806 307, each of the four wheels comprises an active transmitter, and partly even an additional transmitter in the spare tire. When a number of receiving devices (antenna, receiver) are provided, disadvantageously and assuming usual transmitting field densities, the signal can be received in every receiving device, in the worst case even in a neighboring vehicle, because transmitters generally use the same carrier frequency range. When developing a transmission device for tire condition variables, there is the problem in the application of high-frequency methods that one objective is to achieve a sufficient radius of the service area, while additionally another objective is to appropriately suppress common channel interferences or avoid other undesirable couplings between several transmitters and receiving devices.SUMMARY OF THE INVENTION
An object of the present invention is to overcome these shortcomings.
This object is achieved by a transmission device comprising one or a plurality of sensor subassemblies which are arranged in a wheel mounted rotatably at the body by way of wheel hub, and with a coupling device integrated into the wheel hub and composed of a rotor and a non-rotating stator for producing a field coupling, and whose one or more field coupling elements are arranged opposite each other, isolated by a narrow air slot, wherein an energy and/or signal coupling takes place by way of electric fields and/or magnetic fields, and/or electromagnetic fields.
The transmission device of the invention, which is also referred to as ‘wheel-hub coupler’ in the following, is used to transmit signals about tire condition variables from a wheel to an electronic evaluating or control unit arranged in the area of the vehicle body of a motor vehicle. Preferably, this control unit is an existing electronic controlling/regulating unit (ECU) for a motor vehicle brake system (ABS, ESP, etc.).
The transmitted tire condition variables are preferably one or a plurality of the variables air pressure, air temperature, tire temperature, characteristics of the type of tire, characteristics of the tire operating condition, or other wheel parameters that are interesting for a driving dynamics control such as lateral tire force, wheel torque, or tire contact force.
To transmit these characteristic quantities, sensor subassemblies are combined with coupling assemblies and, as the case may be, energy transmitting assemblies in the system of the invention in such a fashion that the desired sensor information can be measured in the rotatably mounted wheel and transmitted into the area of the vehicle body.
A fundamental idea on which the invention is based is the application and technical implementation of per se known general telemetric principles to the problem of transmitting condition variables out of the interior of a motor vehicle tire. The information to be transmitted must be conducted through the tire rubber, especially through the sidewall of the tire. To this end, sending/reception antennas are favorably employed, always having a considerable distance of a minimum of a few centimeters up to a maximum of some meters from each other. Three classes can be distinguished from each other in telemetry. Following formerly usual designations, these classes are the so-called active telemetry, the semi-active telemetry and the so-called passive telemetry. In the active telemetry, e.g. its own battery feeds the transmitter in the area of the sensor system. In the semi-active telemetry, the transmitter stage is supplied with alternating current energy, e.g. through a transformer, which is rectified and used instead of a battery. In the passive telemetry, the ‘transmitter’ is e.g. an oscillation circuit that is either excited by high-frequency pulse packs or reacts on the transmitter circuit by way of a loose coupling. The electric representation of the condition variable obtained by means of sensors modulates the oscillation circuit in its damping or frequency of resonance. This is detected on the excitation side.
The invention further relates to a vehicle wheel equipped with sensors and comprising a wheel rim, a pneumatic tire and one or more sensor assemblies and/or energy transmitting assemblies rotating with the wheel. In a favorable embodiment of the vehicle wheel that is equipped with sensors, the tire, wheel rim, the measuring device and the components for producing an electric connection form a fixed, non-detachable compound arrangement with the wheel-hub coupler that is fabricated and exchanged as a unit.
This unit is screwed onto a wheel hub with a factory-made and integrated wheel-hub coupler during the assembly or a later exchange. Preferably, an appropriate plug coupling is provided at the wheel and, correspondingly, at the wheel-hub coupler for the further transmission of the tire condition variables to the wheel-hub coupler so that the necessary electric connection is favorably made automatically when the wheel is mounted to the hub.
According to a preferred embodiment, a sensor measuring device is attached in the tread area of the tire, especially to the inside surface of the tire tread. This sensor measuring device is either a unit made up of active or passive electronic components or a strobe applied to the tire tread (mirror, measuring gauge, cross hairs, optically activatable materials, etc.) which is scanned by a beam of the signal transmission subassembly arranged on the wheel rim for determining the desired physical quantity.
Further preferred embodiments of the invention can be gathered from the subsequent description of the Figures serving for a more detailed explanation of the invention.
In the drawings,
Three embodiments for exemplary arrangements with different energy supply concepts are represented in the diagrammatic view in
The measured quantity MG is detected by the measuring device MV (reference numeral 14 in
With reference to
The illustration in
An arrangement is illustrated in
Rotor 6a and stator 6b of the transmission device (‘wheel-hub coupler’) of the invention respectively include flat coils (rotor winding 20 and stator winding 22) in
1. A transmission device for motor vehicles for transmitting signals about tire condition variables from a wheel to an electronic evaluating or control unit arranged in an area of a vehicle body, comprising
- at least one sensor subassembly (14, 15, 44) for the detection of tire condition variable, the at least sensor subassembly being arranged in a wheel mounted rotatably at the body by way of wheel hub (3), and
- a coupling device integrated into the wheel hub and composed of a rotor and a non-rotating stator for producing a field coupling, and including field coupling elements (20, 22, 27a, 27b, 29a, 29b, 30a, 30b, 34a, 34b, 39a, 39b, 42, 43) arranged opposite each other, isolated by a narrow air slot (24),
- wherein the wheel has a tire with a tread area and the at least one sensor subassembly is mounted in the tread area of the tire,
- wherein a rotating part of a coupling device for establishing an electrically conductive and detachable connection of the sensor device with a non-rotating part of the coupling device is arranged in the vehicle wheel,
- and wherein an energy supply subassembly (13′, 44) cooperates with the at least one sensor subassembly (15) stationarily fixed in the tread area of the tire by way of a field coupling (16) for the energy supply of the measuring device, wherein the transmission of energy occurs in the way of a transponder.
2. The device as claimed in claim 1,
- further comprising plug connectors on the rotor side and the stator side.
3. The device as claimed in claim 1,
- further comprising an integrated electromechanical coupling device (6a, 6b) on the wheel hub (3).
4. The device as claimed in claim 1,
- further comprising a cable-type electric signal plug coupling (7a, 11, 12) from the wheel hub to a pick-up for measuring data.
5. The device as claimed in claim 1,
- wherein the coupling device comprises flat coils, composed of a rotor with rotor winding (20) and a stator with stator winding (22).
6. The device as claimed in claim 1,
- wherein the coupling device is constructed with cylinder coils embracing each other, composed of a rotor (25) with an integrated rotor winding and a stator (26) with an integrated stator winding.
7. The device as claimed in claim 1,
- wherein stator and rotor of the coupling device are mechanically connected to parts at least one ball bearing (19) installed into the wheel hub.
8. The device as claimed in claim 1,
- wherein the base members of rotor and stator are made of an electrically and magnetically non-conductive material.
9. The device as claimed in claim 1,
- wherein the coupling device is designed with two single-layer windings (27a, 27b) embedded in ferritic shells (28a, 28b).
10. The device as claimed in claim 9,
- wherein the coupling device is designed with multi-layer windings (29a, 29b) directly embedded in the associated base members.
11. The device as claimed in claim 10,
- wherein the coupling device is designed with two windings (30a, 30b) embedded in shielding sheet-metal shells (31a, 31b).
12. The device as claimed in claim 11,
- wherein the coupling device is designed with two windings (32a, 32b) embedded in shielding sheet-metal shells (33a, 33b) and two additional windings (34a, 34b) embedded in ferritic shells (35a, 35b).
13. The device as claimed in claim 12,
- further comprising a dynamo (41) integrated into the coupling device for producing a supply voltage for the operation of the electronic circuit in the sensor subassembly.
14. The device as claimed in claim 13,
- wherein the dynamo is made up of a ring of permanent-magnetic segments (37) on the stator side and coil arrangements (38a) with iron cores (38b) on the rotor side.
15. The wheel as claimed in claim 1,
- wherein the sensor subassembly comprises a sensor element (14, 15, 44) and a signal transmission subassembly (13, 13′), wherein the sensor element and the signal transmission subassembly are integrated into a joint element.
16. The wheel as claimed in claim 1,
- wherein the sensor subassembly comprises at least one sensor with an electronic circuit for conditioning sensor signals.
17. The wheel as claimed in claim 1,
- wherein the at least one sensor subassembly (15) is integrated into the tire.
18. The wheel as claimed in claim 1,
- wherein an energy transmission subassembly (13′, 44) is provided for the energy supply of at least one sensor subassembly (15).
19. The wheel as claimed in claim 1,
- wherein the sensor subassembly is supplied with direct current energy by means of a battery integrated into the sensor subassembly.
20. The wheel as claimed in claim 1,
- wherein a signal transmission subassembly (13′, 44) cooperates with a sensor subassembly (15) stationarily fixed in the tread area of the tire by way of a field coupling (16) for the signal transmission of the measuring device.
21. The wheel as claimed in claim 1,
- wherein a generator integrated into the sensor subassembly supplies the sensor subassembly (15) with direct current energy.
22. The wheel as claimed in claim 1,
- wherein a cable is integrated into the wheel rim having a plug as output towards the coupling device and a wheel rim plug receptacle on the tire side which latter permits an electromechanical plug coupling towards the tire's interior and in which the sensor subassembly can be slipped on and fixed in an electromechanically stationary fashion.
23. The wheel as claimed in claim 22,
- wherein the wheel rim plug receptacle is stationarily integrated into the wheel rim member in such a fashion that it projects into the tire's interior in an air-tight manner.
24. The wheel as claimed in claim 1,
- wherein the sensor subassembly produces tire condition signals by means of electronic sensor means and relays the signals by way of the coupling device to another electronic device.
25. The wheel as claimed in claim 1,
- wherein the tire condition variables relate to at least one quantity out of a group of quantities consisting of air pressure, air temperature and tire temperature.
26. The wheel as claimed in claim 1,
- wherein the tire condition variables relate to at least one quantity out of a group of quantities consisting of the type of tire and operating conditions of the tire.
Filed: Sep 27, 2002
Date of Patent: Apr 24, 2007
Patent Publication Number: 20040244474
Assignee: Continental Teves AG & Co., OHG (Frankfurt)
Inventors: Helmut Fennel (Bad Soden), Peter Lohberg (Friedrichsdorf)
Primary Examiner: Daryl C Pope
Application Number: 10/491,742
International Classification: B60C 23/00 (20060101);